Considerable controversy presently exists concerning the role of cyclic nucleotides in mediating the actions of gonadotropins at the ovarian level. The general elusiveness to date of definitive information on the role of cyclic nucleotides in cellular regulation suggests that the approaches being used may not be the very best. Recently developed immunocytochemical techniques for the cellular localization of both nucleotides suggest that the specificity of hormone action may depend upon the differential effect on local intracellular levels of the cyclic nucleotides. Thus, insight into the role of the cyclic nucleotides in the mediation of gonadotropic hormone action might best be ascertained by determining the localization and intensity of the nucleotides in specific cell types before and after hormonal stimulation. These experiments are intended to evaluate the hypothesis that gonadotropins may mediate their actions by promoting intracellular changes in cyclic nucleotide distribution and/or intensity. In order to evaluate this hypothesis, we will determine the localization patterns and intensities of cAMP and cGMP in ovarian tissue using immunocytochemical procedures before and after administration of gonadotropins (FSH and LH). The experiments are also intended to determine if there are differential effects of FSH and LH upon localization patterns and intensities within specific cell types within the ovary and if these effects can be correlated with 1) steroid production and 2) with the maturation of the cumulus-oocyte complex preceding ovulation.